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ADI’S iCOUPLER DIGITAL ISOLATION IC TECHNOLOGY COMPRISES A TRANSFORMER WITH THICK POLYIMIDE INSULATION. DIGITAL ISOLATORS USE FOUNDRY CMOS PROCESSES. TRANSFORMERS ARE DIFFERENTIAL AND PROVIDE EXCELLENT COMMON-MODE TRANSIENT IMMUNITY.
in magnetics sensing have yielded a new generation of contactless cur- rent sensors delivering no power loss with high bandwidth and accuracy, as well as accurate and robust position sensors for end-of-shaft and off-shaft configurations. There are between 15 and 30 current sensors targeted for deployment in a typical plug-in hybrid EV,1 with rotation and position sensors monitoring traction motor functions. Sensing accuracy and robustness to the stray field are critical attributes for measuring and maintaining efficiencies across EV power subsystems.
End-to-end efficiency
Looking holistically at all elements in the EV powertrain — from the battery to the traction inverter to the support- ing components and beyond — ADI sees myriad opportunities to improve EVs in a manner that enhances overall power efficiency and extends EV driving range. Digital isolation is one of the many important parts of the equation, as SiC power-switching technology penetrates the EV traction inverter.
Likewise, automotive OEMs can lever- age a multidisciplined approach to EV optimization to help ensure that all available power-monitoring and control devices are working in close concert for maximum performance and efficiency. In turn, they can help to overcome the last remaining barriers to mainstream consumer EV adoption — vehicle driv- ing range and cost — while helping to ensure a greener future for all.
Timothé Rossignol
is a marketing manager at Analog Devices.
This not only helps with efficiency but also enables board space and cost sav- ings by eliminating the need for exter- nal buffers allocated per gate driver. Conversely, under certain conditions, the system may need to switch more slowly to achieve optimal efficiency, or even switch in stages, which stud- ies have shown can increase efficiency further. ADI provides an adjustable slew rate to allow users to do this, and the removal of external buffers eliminates further obstacles.
Elements in a system
It’s important to note that the combined value and performance of the gate driver and SiC switch solution can be completely negated by compromises or inefficiencies in the surrounding components.
A holistic view of the EV reveals addi- tional opportunities for optimizing drive- train power efficiencies, which are criti- cal for exploiting the maximum usable battery capacity while ensuring safe and reliable operations. The quality of the BMS directly impacts the miles per charge that an EV can deliver, maximizes the battery’s overall lifetime, and, as a
result, lowers the total cost of ownership.
In terms of power management, the ability to overcome complex electro- magnetic interference (EMI) challenges — without compromising BOM costs or PCB footprint — becomes paramount. Power efficiency, thermal performance, and packaging remain critical consider- ations at the power supply layer, regard- less of whether the layer is for an iso- lated gate driver power supply circuit or auxiliary high-voltage-to-low-voltage DC-to-DC circuit. In all cases, the ability to neutralize EMI issues takes on greater importance for EV designers. EMC is a critical pain point when it comes to switching for multiple power supplies, and superior EMC can go a long way toward shortening testing cycles and reducing design complexities, thereby accelerating time to market.
Deeper into the ecosystem of sup- porting componentry, advancements
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REFERENCES
1R. Dixon. “MEMS Sensors for the Car of the Future.” 4th Annual Automotive Sensors and Electronics Summit, February 2019.
Resources Delivering on the EV Range Extension Promise of SiC in Traction Inverters